Opening the shutter

The sky’s the limit:
Bob Vold logs in at the computer at the new Thomas Harriott Observatory atop Small Hall. The computer controls the telescope mount and also rotates the observatory dome to point the telescope at any of a galaxy of celestial objects.

More people will use the Thomas Harriott Observatory than you think

by Joseph McClain
| January 7, 2013

The transit of Venus is, at best, a twice-in-a-lifetime
event. Transits come in pairs, eight years apart, and these pairs come more
than 100 years apart. If you didn’t see the planet of love pass between the
earth and the sun on June 5, you’ll have to wait until 2117 for the next chance.

Bob Vold, like many astronomers, missed the 2004 transit of
Venus because of clouds. On June 5, 2012—transit day—it was cloudy again. The
weather forecast predicted the cloud cover might start to clear, encouragement
enough for Vold to start calling and e-mailing. He had a brand new observatory
to show off and there was no occasion better than the transit of Venus for a
coming-out party.

Vold is a professor of applied science and
also the director of William & Mary’s Thomas Harriot Observatory. The
observatory was the last major component of the expansion and renovation of
Small Hall. The new dome and its 14-inch computer-controlled telescope will
give William & Mary much improved astronomical functionality.

More people will use the observatory than you might think.
The physics department
requires all its majors to complete a senior project or honors thesis. Vold
says that usually two or three seniors each year pursue an astronomy project.
“We haven’t had any the last couple of years because the building was being
renovated,” Vold said. “But now I expect we’ll have an upswing.”

Limited
space/unlimited potential (unless it’s cloudy)

The new observatory will serve students enrolled in
introductory astronomy, a popular way for William & Mary’s humanities and
social-science majors to fill science GER requirements. Images from the 14-inch,
computer-controlled Meade telescope can be piped down into the building’s
lecture halls. Logistics would preclude intro lab sections from using the big
scope directly: Vold says he’s comfortable with five to maybe eight people in
the observatory dome at one time, “unless they start to mill around too much.”

At the transit party, Vold called eight-person shifts—warned
of the dangers of excess milling—into the dome. Others took turns at eight-inch
telescopes set up by volunteers from the Student Physics Society. There was
more waiting than watching, as broken cloud cover drifted across the sun, which
broke through the clouds with enough regularity to give the partiers a view of
Venus, a teeny black circle as seen through the solar filters, crawl across the
surface of the sun.

Cloudy skies and light pollution are the twin curses of
telescope astronomy, and Vold has developed a philosophy for unpredictable
conditions.

“It’s like having a 15-year-old,” he says. “You just have to
be flexible. You schedule something for eight o’clock at night. If it’s cloudy,
you schedule it for the next eight o’clock at night.”

One does not simply
walk in and type “crab nebula”

So that he doesn’t have to be on hand for each and every
clear night, Vold
is training a few students to operate the observatory. The observatory’s
computer can point the telescope and rotate the dome to reveal any of a
constellation of heavenly objects. It’s not a steep learning curve, but, Vold
says, one does not simply walk into the observatory and type “crab nebula.”

“The typical young student’s approach to learning computers,
which usually works really well, is to just try everything out until you figure
out how it works,” Vold explained. “If you do that with a computer-guided
telescope mount you can ruin a lot of things.”

The dome itself requires careful tending, too. The first
rule, Vold says, is to keep the door shut. “If the dome starts to rotate while
the door is open, it will come off its track. It can be fixed, but it takes
five or six people to lift it back onto the track and we just don’t want to go
through that hassle.”

Vold teaches an annual freshman seminar in astrophotography
and says he’s found that even experienced astronomers relate better to photos
of the heavens than to direct observation through a telescope.

“You look through the eyepiece of all but very large
telescopes and whatever there is to be seen is in black and white, because the
light is not strong enough to turn on the color sensors in your eye,” he said.
“The camera works a little differently. The camera just collects photons of all
colors—it doesn’t matter what color, it just collects them as long as the
shutter is open.”

Therefore, he explained, the camera is thousands of times
more sensitive than your eye. It’s the reason why you won’t be able to look
through any telescope and see with your eye an image to match those stunning
shots of far-off places in the heavens.

A family tradition of
astronomy

Vold’s interest in astronomy began at the age of six. He
comes by it honestly, as his mother’s grandfather was Robert Grant Aitken, director
of the Lick Observatory in California. Vold inherited some of his grandfather’s
notebooks and negotiated a deal with the current Lick administration. They got
the notebooks and Vold got to take a break from his job doing astrophotography
at the Thomas Harriot Observatory to spend some time doing astrophotography on
the Great Lick Refractor—his great-grandfather’s telescope, 57 feet long, built
in 1879 and still in use.

Vold says only half the freshmen in his astrophotography
seminar are headed for science majors, a mix of intellects that makes for “an
interesting clash of ideas,” as he puts it.

“The science students are entranced by things like how do
you measure the distance to stars—all the quantitative things you would think
somebody in science might want to do,” he said. “The non-science students look
at the pictures and just go wow. Then they try to apply basic ideas of form and
artistic merit to the photos.”